1. Field of the Invention
The present invention relates to a remote control device for a vehicle comprising: a portable transmitter configured to repeatedly transmit a signal for giving an instruction to activate an activation device mounted in a vehicle, in response to an operation of a manipulator which is performed continuously for a predetermined time or more; and a vehicle-side receiver provided in the vehicle to activate the activation device on the basis of the signal transmitted from the portable transmitter.
2. Description of the Related Art
Japanese Patent Application Laid-open No. 2004-239002 has made known a system in which an activation device provided in a vehicle, such as a power window, is activated by pressing and holding an operation button of a portable transmitter owned by vehicle user. In such a system, when the operation button is pressed and held, the portable transmitter transmits a signal of a first frame type including a synchronization frame, a header, and a data frame, and then repeatedly transmits a signal of a second frame type in which the synchronization frame is shorter than that of the first frame type but the data frame is the same as that of the first frame type.
Since a signal having a long data length is repeatedly transmitted from the portable transmitter in the pressing and holding of the operation button, a battery of the portable transmitter is consumed rapidly and the battery life is reduced.
Meanwhile, the following system is known from Japanese Patent Application Laid-open No. 2003-110554. When encrypted data is repeatedly transmitted from a portable transmitter and a signal of the same data is received, a stored code is called and used without decoding the received signal thereby enabling reduction of a processing load of a CPU or the like for decoding. However, this operation is performed in a receiver provided in a vehicle and does not reduce battery power consumption of the portable transmitter.